Add new statistics which reflect the average time a task is running on the CPU and the sum of the tasks' running on a runqueue. The latter is named usage_avg_contrib.
The rq's usage_avg_contrib will be used to check if a rq is overloaded or not instead of trying to compute how many task a group of CPUs can handle
Signed-off-by: Vincent Guittot vincent.guittot@linaro.org --- include/linux/sched.h | 4 ++-- kernel/sched/fair.c | 47 ++++++++++++++++++++++++++++++++++++++++++----- kernel/sched/sched.h | 2 +- 3 files changed, 45 insertions(+), 8 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h index 0376b05..6893d94 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1073,10 +1073,10 @@ struct sched_avg { * above by 1024/(1-y). Thus we only need a u32 to store them for all * choices of y < 1-2^(-32)*1024. */ - u32 runnable_avg_sum, runnable_avg_period; + u32 runnable_avg_sum, runnable_avg_period, running_avg_sum; u64 last_runnable_update; s64 decay_count; - unsigned long load_avg_contrib; + unsigned long load_avg_contrib, usage_avg_contrib; };
#ifdef CONFIG_SCHEDSTATS diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 1cde8dd..8bd57df 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -676,7 +676,7 @@ void init_task_runnable_average(struct task_struct *p)
p->se.avg.decay_count = 0; slice = sched_slice(task_cfs_rq(p), &p->se) >> 10; - p->se.avg.runnable_avg_sum = slice; + p->se.avg.runnable_avg_sum = p->se.avg.running_avg_sum = slice; p->se.avg.runnable_avg_period = slice; __update_task_entity_contrib(&p->se); } @@ -2292,7 +2292,8 @@ static u32 __compute_runnable_contrib(u64 n) */ static __always_inline int __update_entity_runnable_avg(u64 now, struct sched_avg *sa, - int runnable) + int runnable, + int running) { u64 delta, periods; u32 runnable_contrib; @@ -2331,6 +2332,8 @@ static __always_inline int __update_entity_runnable_avg(u64 now, delta_w = 1024 - delta_w; if (runnable) sa->runnable_avg_sum += delta_w; + if (running) + sa->running_avg_sum += delta_w; sa->runnable_avg_period += delta_w;
delta -= delta_w; @@ -2341,6 +2344,8 @@ static __always_inline int __update_entity_runnable_avg(u64 now,
sa->runnable_avg_sum = decay_load(sa->runnable_avg_sum, periods + 1); + sa->running_avg_sum = decay_load(sa->running_avg_sum, + periods + 1); sa->runnable_avg_period = decay_load(sa->runnable_avg_period, periods + 1);
@@ -2348,12 +2353,16 @@ static __always_inline int __update_entity_runnable_avg(u64 now, runnable_contrib = __compute_runnable_contrib(periods); if (runnable) sa->runnable_avg_sum += runnable_contrib; + if (running) + sa->running_avg_sum += runnable_contrib; sa->runnable_avg_period += runnable_contrib; }
/* Remainder of delta accrued against u_0` */ if (runnable) sa->runnable_avg_sum += delta; + if (running) + sa->running_avg_sum += delta; sa->runnable_avg_period += delta;
return decayed; @@ -2493,6 +2502,27 @@ static long __update_entity_load_avg_contrib(struct sched_entity *se) return se->avg.load_avg_contrib - old_contrib; }
+ +static inline void __update_task_entity_usage(struct sched_entity *se) +{ + u32 contrib; + + /* avoid overflowing a 32-bit type w/ SCHED_LOAD_SCALE */ + contrib = se->avg.running_avg_sum * scale_load_down(SCHED_LOAD_SCALE); + contrib /= (se->avg.runnable_avg_period + 1); + se->avg.usage_avg_contrib = scale_load(contrib); +} + +static long __update_entity_usage_avg_contrib(struct sched_entity *se) +{ + long old_contrib = se->avg.usage_avg_contrib; + + if (entity_is_task(se)) + __update_task_entity_usage(se); + + return se->avg.usage_avg_contrib - old_contrib; +} + static inline void subtract_blocked_load_contrib(struct cfs_rq *cfs_rq, long load_contrib) { @@ -2509,7 +2539,7 @@ static inline void update_entity_load_avg(struct sched_entity *se, int update_cfs_rq) { struct cfs_rq *cfs_rq = cfs_rq_of(se); - long contrib_delta; + long contrib_delta, usage_delta; u64 now;
/* @@ -2521,16 +2551,20 @@ static inline void update_entity_load_avg(struct sched_entity *se, else now = cfs_rq_clock_task(group_cfs_rq(se));
- if (!__update_entity_runnable_avg(now, &se->avg, se->on_rq)) + if (!__update_entity_runnable_avg(now, &se->avg, se->on_rq, + cfs_rq->curr == se)) return;
contrib_delta = __update_entity_load_avg_contrib(se); + usage_delta = __update_entity_usage_avg_contrib(se);
if (!update_cfs_rq) return;
- if (se->on_rq) + if (se->on_rq) { cfs_rq->runnable_load_avg += contrib_delta; + cfs_rq->usage_load_avg += usage_delta; + } else subtract_blocked_load_contrib(cfs_rq, -contrib_delta); } @@ -2607,6 +2641,7 @@ static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq, }
cfs_rq->runnable_load_avg += se->avg.load_avg_contrib; + cfs_rq->usage_load_avg += se->avg.usage_avg_contrib; /* we force update consideration on load-balancer moves */ update_cfs_rq_blocked_load(cfs_rq, !wakeup); } @@ -2625,6 +2660,7 @@ static inline void dequeue_entity_load_avg(struct cfs_rq *cfs_rq, update_cfs_rq_blocked_load(cfs_rq, !sleep);
cfs_rq->runnable_load_avg -= se->avg.load_avg_contrib; + cfs_rq->usage_load_avg -= se->avg.usage_avg_contrib; if (sleep) { cfs_rq->blocked_load_avg += se->avg.load_avg_contrib; se->avg.decay_count = atomic64_read(&cfs_rq->decay_counter); @@ -2962,6 +2998,7 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) */ update_stats_wait_end(cfs_rq, se); __dequeue_entity(cfs_rq, se); + update_entity_load_avg(se, 1); }
update_stats_curr_start(cfs_rq, se); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 5a8ef50..e5ab9b1 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -336,7 +336,7 @@ struct cfs_rq { * This allows for the description of both thread and group usage (in * the FAIR_GROUP_SCHED case). */ - unsigned long runnable_load_avg, blocked_load_avg; + unsigned long runnable_load_avg, blocked_load_avg, usage_load_avg; atomic64_t decay_counter; u64 last_decay; atomic_long_t removed_load;